CZ288617B6 - Catalytic mixture for oxidative ammonolysis of alkyl pyridines - Google Patents

Abstract

A new catalytic composition, comprising the oxides of vanadium, titanium, zirconium and molybdenum in molar ratio of vanadium pentaoxide to titanium dioxide to zirconium oxide ranging from 1:1.2 to 1:12.25 is disclosed. The composition contains 0.54 to 2.6 percent by weight of molybdenum trioxide, based on the amount of vanadium pentaoxide. The new catalytic composition is applied in the oxidative ammonolysis of alkyl pyridines. The oxidative ammonolysis of alkyl pyridines is characterized in that alkyl pyridine is passed together with ammonia, an oxygen-containing gas and optionally steam through the invented catalytic composition at a temperature ranging from 280 to 400 degC.

Description

Catalytic mixture for oxidative ammonolysis of alkylpyridines

Technical field

The present invention relates to catalyst compositions, their use in oxidative ammonolysis of alkypyridines, and to a process for preparing cyanopyridines.

The catalyst mixtures are preferably useful for the oxidative ammonolysis of 3-methylpyridine and 2-methyl-5-ethylpyridine to the corresponding 3-cyanopyridine.

3-Cyanopyridine is an intermediate for nicotinic acid and nicotinic amide, which are essential vitamins of the B-complex.

BACKGROUND OF THE INVENTION

Oxidative ammonolysis of alkylpyridines is well known in the art. Many types of catalyst systems have been described, but to date no production method is known which would suitably meet the needs of a commercial production method on a technical scale.

Reference is made to USSR 891 142, which describes a catalyst for the ammonolysis of alkylpyridines which consists of oxides of vanadium, tin and titanium. The maximum yield achieved for conversion (e.g.) for 2-methyl-ethylpyridine is 63%. The main disadvantage of this catalyst mixture is therefore its low activity and selectivity.

It is further known from Swiss patent 595 350 that 2-methyl-5-ethylpyridine can be converted to 3-cyanopyridine on a mixed oxide supported catalyst consisting of vanadium, zirconium or titanium oxides and optionally tungsten. The yields obtained with this catalyst are between 60% and 75%. Also, this catalyst is not satisfactory due to its low selectivity and activity. A further disadvantage is the somewhat complicated process for producing this supported catalyst.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a catalyst composition with further improved catalytic activity and performance and thus to provide an improved manufacturing process for oxidative ammonolysis of alkylpyridines in particular in relation to selectivity and yield.

The catalyst composition of the present invention according to claim 1 contains oxides of vanadium, zirconium and molybdenum in a molar ratio of V ₂ O ₅ kTiO ₂ kZrO ₂ from 1:12:25 and contains from 0.54 to 2.6 weight percent MoO 3 based on V ₂ Os.

A preferred catalyst mixture has a molar ratio of V ₂ O _{5 to} TiO _{2 to} ZrO ₂ from 1: 3: 4 to 1: 8: 16 and a MoO ₃ content of from 0.54 to 1.15 weight percent based on V ₂ O ₅ .

The corresponding oxides themselves may be used to prepare the catalyst mixture, but it is also possible to use starting compounds which are later converted to oxides. Such starting compounds are, for example: vanadium pentoxide, ammonium metavanadate; zirconium dioxide, zirconium chloride; titanium dioxide, metatitanium acid; and for molybdenum oxide ammonium molybdate.

Generally, the preparation of the catalyst mixture can be accomplished by mixing the ingredients in a suitable grinding machine, granulating or tableting the mixture, and finally drying the granules or tablets at a temperature of about 100 ° C to 120 ° C in an air stream. The catalyst is preferably subsequently subjected to heat at temperatures up to 650 ° C. The easy-to-prepare catalyst can then be charged into the catalyst

A reactor in which, after the activation phase under the reaction conditions, it is able to demonstrate its properties in terms of both high activity and selectivity at high loads of alkylpyridines and also in terms of long use time. The catalyst mixture of the present invention is particularly suitable for the oxidative ammonolysis of alkylpyridines in the presence of ammonia, an oxygen-containing gas and, if necessary, water vapor. The advantage of applying the catalyst mixture is the conversion of 3-methylpyridine or 2-methyl-5-ethylpyridine to 3-cyanopyridine. The following manufacturing process conditions were confirmed.

Air is generally used as the oxygen-containing gas. Air provides the advantage that oxygen is already diluted with inert components. The oxygen partial pressure can advantageously be controlled by further diluting 10 with a suitable inert gas, for example nitrogen, or by recycling some or most of the oxygen-depleted waste gases.

There are two advantages over the processes known in the art for the conversion of 3-methylpyridine, which according to the invention not only does not require a water vapor preparation but also uses a practically stoichiometric amount or a small molar excess of ammonia.

The gaseous reactants fed in the case of oxidative ammonolysis of 3-methylpyridine are thus composed in a molar ratio of 3-methylpyridine to ammonia and to air (calculated on the basis of oxygen from 1: 1: 1.5 to 1: 8.5: 60).

The preferred feed gas is composed in a molar ratio of 3-methylpyridine to ammonia and to air (calculated on an oxygen basis) of from 1: 1: 2 to 1: 4: 60.

Thus, the gaseous reactants fed in the case of 2-methyl-5-ethylpyridine oxidative ammonolysis are 25 composed in a molar ratio of 2-methyl-5-ethylpyridine to ammonia and air (calculated on

O ₂ ) and water vapor from 1: 20: 20: 60 to 1: 60: 70: 330.

The temperature of the reaction zone of the catalyst bed is suitably between 280 ° C and 400 ° C and preferably between 310 ° C and 380 ° C.

The characteristics of the catalyst composition, also with respect to durability, allow the production process to run continuously on a large scale.

The maximum yield achieved with 3-cyanopyridine at a feed rate of up to 150 g of 3-methylpyridine per liter of catalyst 35 is 99% per hour and with up to 120 g of 2-methyl-5-ethylpyridine per liter of catalyst is 85%.

DETAILED DESCRIPTION OF THE INVENTION

Example 1

36.4 g of vanadium pentoxide, 48.0 g of titanium dioxide, 192.7 g of zirconium dioxide and 0.42 g of 45 molbydenum oxide in molar ratios of V ₂ O ₅ : TiO ₂ : ZrO ₂ = 1: 3: 8 and 1.15 % by weight of MoO _3, based on vanadium pentoxide, was ground and blended in a ball mill. The mixture was compressed into 5 x 5 mm granules and heated at 100-120 ° C in a stream of air for 6 hours. The obtained catalyst of 60 cm 3 (82 g) was charged into a stainless steel tubular reactor (20 mm ID, 1000 mm length). A catalyst mixture of 2-methyl-5-ethylpyridine, air, ammonia and water vapor was passed through the catalyst bed at 340 ° C.

The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^_l) was: 2-methyl-5-ethyl-72 gl ^_1, air - 1500 1, ammonia - 228 gl ¹ and the water - 583.3 gr'h- ¹ , which corresponds to the molar ratio of 2-methyl-5-ethylpyridine to oxygen, ammonia and quodum 1: 47: 45: 108. Thus, 21.6 g of 2-methyl-5-ethylpyridine were introduced over 10 hours.

-2GB 288617 B6

The conversion was complete. 15.0 g of 3-cyanopyridine were obtained, corresponding to a yield of 80.5% of theory.

The production of 3-cyanopyridine was 49.8 gr ^-1 .

Example 2

The catalyst described in Example 1 was used. A mixture consisting of 3-methylpyridine, air and ammonia was passed through the catalyst at a temperature of 330 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^_1) was: 3-methylpyridine - 84 gl ^_1, air - 2000 1, ammonia - 9.92 gr ^ ^'1 corresponding to a ratio of 3 molámímu methylpyridine: O _2: NH ₃ = 1: 40: 1.3.

Thus, 25.5 g of 3-methylpyridine were introduced over 10 hours. The convention was complete. 26.8 g of 3-cyanopyridine was obtained, which corresponds to a yield of 95.0 moles = theory. Production of 3-cyanopyridine was 89.2 gl ^{_ h _I.}

Example 3

The catalyst was introduced from 36.4 g of vanadium pentoxide, 64.0 g of titanium dioxide, 98.6 g of zirconium dioxide and 0.2 g of MoO ₃ in molar porn V ₂ O ₅ : TiO ₂ : ZrO ₂ = 1: 4: 4 and 0.54 wt% MoO ₃ based on V ₂ O ₅ . The catalyst was prepared as described in Example 1. A feed gas consisting of 2-methyl-5-ethylpyridine, ammonia and water vapor was passed through a catalyst bed (60 cm ³ ) at 320 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^_1) was: 2-methyl-5-ethylpyridine -72gr'h ^_l, air - 5001 1, ammonia 228 gl ^_I, water 700 gl ^ h ' ¹ , which corresponds to the molar ratio of 2-methyl-5-ethylpyridine: O ₂ : NH ₃ : H ₂ O 1: 47: 45: 130. Thus, 21.6 g of 2-methyl-5-ethylpyridine were introduced over 10 hours. The conversion was complete. 15.3 g of 3-cyanopyridine were obtained, corresponding to a yield of 82.2% based on the 2-methyl-5-ethylpyridine introduced. The production of 3-cyanopyridine was 50.8 g ^/ hr.

Example 4

A catalyst with a molar ratio of V ₂ O ₅ : TiO ₂ : ZrO ₂ = 1: 4: 4 and 0.90 wt% MoO ₃ based on V ₂ Os was prepared according to Example 1. The mixture consisting of 3-methylpyridine, air and ammonia was passed through the catalyst at 330 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^{_1 _1} h) was: 3-methylpyridine - 84 gl ^_1, air - 2000 1, ammonia - 9.92 gl ^-1 h ^-1 corresponding molámímu ratio of 3-methylpyridine: O ₂ NH ₃ 1:40: 1.3.

Thus, 25.2 g of 2-methyl-5-ethylpyridine was prepared over 10 hours. The conversion was complete. 27.3 g of 3-cyanopyridine were obtained, corresponding to a yield of 97.9% of theory. Production of 3-cyanopyridine was 91.0 gl ^ h ^'first

Example 5

A catalyst with a molar ratio of V ₂ O ₅ : TiO ₂ : ZrO ₂ = 1: 4: 8 and 0.98 wt% MoO ₃ based on V ₂ O ₅ was prepared according to Example 1. A mixture consisting of 2-methyl-5-ethylpyridine, air , ammonia and water vapor were passed through the catalyst at 320 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^_1) was: 2-methyl-5-ethyl - 72 gl ^ ^h-1, air - 5001 1, ammonia 228 gl ^{'l _I} h and water - 700gr ^{1h 1} , which corresponds to the molar ratio of 2-methyl-5-ethylpyridine: O ₂ : NH ₃ : H ₂ O 1: 47: 45: 130. Thus, 21.6 g of 2-methyl-5-ethylpyridine were introduced over 10 hours. The conversion was complete. 15.4 g of 3-cyanopyridine were obtained, corresponding to a yield of 83% based on the 2-methyl-5-ethylpyridine introduced. Production of 3-cyanopyridine was 51.3 gl @ ^-1 h.

-3GB 288617 B6

Example 6

A catalyst with a molar ratio of V ₂ O ₅ : TiO ₂ : ZrO ₂ = 1: 4: 8 and 1.15 wt% MoO ₃ was prepared according to Example 1. A mixture consisting of 3-methylpyridine, air and ammonia was passed through 5 catalyst at temperature 325 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^ h ^"1) was: 3-methylpyridine - 168 gl ^_1, air - 2000 1, ammonia - 22.8 gl ^ h ^-1 corresponding to a ratio 3-methylpyridine: O _2: NH ₃ of 1: 40: 1.5. Thus, 50.4 g was delivered over 10 hours

3-methylpyridine. The conversion was complete. 55.8 g of 3-cyanopyridine were obtained, corresponding to 10 yield of 99.0% of theory. Production of 3-cyanopyridine was 186 gr ^l h ^_1.

Example 7

A catalyst with a molar ratio of XSCfyTiCfyZrCL = 1: 4: 8 and 1.15 wt% MoO ₃ based on V ₂ O ₅ was prepared according to Example 1. A mixture of 3-methylpyridine, air and ammonia was passed through the catalyst at 350 ° C . The feed rate (1 gram per liter of catalyst per hour = gr'h '') was: 3-methylpyridine - 218 gl ^-1 h ^-1 , air - 2,000 l, ammonia - 30,35 gl ^ h ^-1 , corresponding to a molar ratio of 3-methylpyridine: O ₂ NH _{3 of} 1: 16: 1.5.

Thus, 65.5 g of 3-methylpyridine were introduced over 10 hours. The conversion was complete. 75.2 g of 3-cyanopyridine were obtained, corresponding to a yield of 99.0% of theory. Production of 3-cyanopyridine was 241.7 gl ^'first

Example 8

1.167 kg of vanadium pentoxide, 2.512 kg of titanium dioxide as metatitanium acid, 6.322 kg of zirconium dioxide and 12.4 g of ammonium paramolybdate (molybdic acid) in a molar ratio of V ₂ O 5: TiO ₂ ZrO ₂ = 1: 4: 8 and 1.05% () ₄ ) ₆ Μθ7θ ₂ 4 4H ₂ O, based on vanadium pentoxide, 30 was kneaded in a two-arm kneader and ground and blended in a ball mill. The mixture was formed into granules of approximately 3x3 mm and heated at 100-120 ° C for 6 hours. The amount of catalyst obtained (1 liter, 1.50 kg) was charged to a tubular reactor made of stainless steel (21 mm ID, length 3 meters). The reagent mixture consisting of 3-methalopyridine, air, nitrogen and ammonia was passed through the catalyst at 340 ° C. 35 The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^_1) was: 3-methylpyridine 80 gl ^-1 h ^ air

200 h ¹ , nitrogen 1 200 h ^-1 , ammonia 37.5 gr'h ', corresponding to a molar ratio of 3-methylpyridine to ammonia and oxygen of 1: 2.6: 2.2. Thus, 1,920 g of 3-methylpyridine was fed over 24 hours. The conversion was 99%. 1,910 g of 3-cyanopyridine were obtained, corresponding to a yield of 89%. Production of 3-cyanopyridine was 79.6 gl ^_1.

Example 9

An amount of the catalyst obtained in Example 8 (985 cm ³ , 1.46 kg) was charged into a tube 45 reactor made of stainless steel (ID 21 mm, length 3 meters). The reagent mixture consisting of 3-methylpyridine, air, recycled waste gas and ammonia was passed through the catalyst at 345 ° C. The feeding rate (gram per 1 liter catalyst per 1 hour = gl ^{_l _1} h) was: 3-methylpyridine 80 gl ^_1 air 180 ^h-1, recycled exhaust gas 1200 h ^_1, ammonia 52.5 gl ^-I H ^-1 , which corresponds to a molar ratio of 3-methylpyridine to ammonia and oxygen of 50: 1: 3.6: 2.0. Thus, 1,890 g of 3-methylpyridine were fed over 24 hours. The conversion was

98.5%. 1,850 g of 3-cyanopyridine were obtained, corresponding to a yield of 88.5%. Production of 3-cyanopyridine was 77 gl ~ 'h ^_l.

-4GB 288617 B6

Example 10

An amount of the catalyst obtained in Example 8 (135 cm ³ , 160 g) was heated at 5820 ° C for 6 hours. The catalyst was charged into a stainless steel tubular reactor (internal diameter mm, length 1000 mm). The reagent mixture consisting of 3-methylpyridine, air, nitrogen and ammonia was passed through the catalyst at 375 ° C. The feed rate was: 3-methylpyridine 11 gh ^-1 (81 gl ^ h ^-1 - gram per 1 liter per hour), air 30 h ^-1 , nitrogen 285 h ^-1 , ammonia 4 gh ^-1 , corresponding to a molar ratio of 3 -methylpyridine to ammonia and oxygen as well as 1: 2: 2.6. Thus, 264 g of 3-methylpyridine was introduced over 24 hours. The conversion was 99%.

261 g of 3-cyanopyridine were obtained, corresponding to a yield of 89%. The production of 3-cyanopyridine was 80 g / hr.

-5GB 288617 B6

WHAT

ZJ JD (0 H

-6GB 288617 B6

Oxidative ammoniumysis of 3-methylpyridine (3-Pic)

c Ϊ5 · £ Q. O production g / 1 cat./h 77.0 84.6 88.4 89.3 9 * 98 139.9 151.3 c molar yield % 82.0 90.0 94.0 95.0 92.5 99.2 0 * 66 conversion % 100 ALIGN! o o T ' 100 ALIGN! 100 ALIGN! 001 100 ALIGN! 100 ALIGN! temperature Noc: 2 ° C 325 330 330 325 330 330 3501 D § Φ Φ φ φ φ 5T φ_ hours <Q Q.> O V * v Ύ— - IN IN •in IN g / 1 cat air 2000 2000 o o o CM o o o CM 2000 2000 o o o CM supply i 3-Pic 84 84 84 84 84 126 136 Catalyst % by weight relative to V ₂ O ₅ r> o p 0.90 0.54 IO 0.54 06 * 0 0.90 0.90 CM 2 N what CM O in CM WHAT in· what what ratio sl in mol CM O H O (O Φ Φ m Φ Φ IO o> * T- •O (Q £ O) o CM CM CM CM co CM 3 ιο CM O.

-7EN 288617 B6

Claims (8)

PATENT CLAIMS A catalytic mixture consisting of vanadium, titanium, zirconium and molybdenum oxides having a molar ratio of vanadium oxide V ₂ O ₅ to titanium dioxide TiO ₂ to zirconia ZrO ₂ from 1: 1: 2 to 1:12:25 and comprising 0.54 to 2.6% by weight of molybdenum oxide% MoO ₃ , based on vanadium pentoxide V ₂ O ₅ . Catalytic composition according to claim 1, having a molar ratio of V ₂ O ₅ to TiO ₂ to ZrO _{2 of} from 1: 3: 4 to 1: 8: 16 and containing from 0.54 to 1.15% MoO _{3 by} weight V ₂ Pers. Use of the catalytic mixture according to claim 1 or 2 for oxidative ammonolysis of alkyl pyridines. Use of the catalytic mixture according to claim 1 or 2 for the oxidative ammonolysis of 3-methylpyridine and 2-methyl-5-ethylpyridine. 5. A process for the preparation of cyanopyridines by oxidative ammonolysis of alkylpyridines 20, in that the alkylpyridine, together with ammonia, the oxygen-containing gas and, if necessary with water vapor, is passed through the catalyst mixture according to claims 1 or 2 at a temperature of from 280 ° C to 400 ° C. A process according to claim 5 for the preparation of 3-cyanopyridine by oxidative ammonolysis 25 of 3-methylpyridine, characterized in that 3-methylpyridine, ammonia and an oxygen-containing gas in a molar ratio of 1: 1: 1.5 to 1: 8.5: 60, based on oxygen O ₂ , are passed through the catalyst mixture of claim 1 or 2 at a temperature of 310 ° C to 380 ° C. A process according to claim 6, wherein the molar ratio The 3-methylpyridine, ammonia and oxygen-containing gas are 1: 1: 2 to 1: 4: 60. A process according to claim 5 for the preparation of 3-cyanopyridine by oxidative ammonolysis of 2-methyl-5-ethylpyridine, characterized in that 2-methyl-5-ethylpyridine, ammonia and oxygen-containing gas and water vapor in a molar ratio of 1:20 : 20: 60 to 1: 60: 70: 330, he's led 35 over the catalyst mixture of claims 1 or 2 at a temperature of 310 ° C to 380 ° C.